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Quiescent
Terms modified by Quiescent Selected AbstractsIncidence, Aggressiveness and In Planta Interactions of Botrytis cinerea and other Filamentous Fungi Quiescent in Grape Berries and Dormant Buds in Central Washington StateJOURNAL OF PHYTOPATHOLOGY, Issue 7 2002F. M. Dugan Abstract Recovery of quiescent filamentous fungi from non-symptomatic grape berries and dormant buds demonstrated dominance of Alternaria, Aureobasidium, Cladosporium, Ulocladium and other dematiaceous hyphomycetes. Up to 78% of berries contained fungi prior to harvest. Botrytis cinerea was recovered from 0.2 to 0.5% of surface-disinfested berries just subsequent to fruit set, and 1.6,4.8% of surface-disinfested, over-wintered dormant buds. In laboratory inoculations of mature grape berries with strains of Alternaria, Aureobasidium, Cladosporium, Ulocladium and Botrytis, only the latter was aggressive in rotting berry fruits. Inoculations with B. cinerea alone and in combination with strains of Alternaria, Aureobasidium, Cladosporium and Ulocladium recovered from grape demonstrated that prior occupation of wound sites by the latter fungi resulted in reduced lesion size compared to inoculation with B. cinerea alone. [source] The expression patterns of Pax7 in satellite cells during overload-induced rat adult skeletal muscle hypertrophyACTA PHYSIOLOGICA, Issue 4 2009M. Ishido Abstract Aim:, Activated satellite cells (SCs) have the ability to reacquire a quiescent, undifferentiated state. Pax7 plays a crucial role in allowing activated SCs to undergo self-renewal. Because the increase in the SC population is induced during overload-induced skeletal muscle hypertrophy, it is possible that Pax7-regulated SC self-renewal is involved in the modulation of the SC population during the functional overload of skeletal muscles. However, the characteristics of the expression patterns of Pax7 in SCs during the functional overload of adult skeletal muscles are poorly understood. Methods:, Using immunohistochemical approaches, we examined the temporal and spatial expression patterns of Pax7 expressed in SCs during the functional overloading of rat skeletal muscles. Results:, The time course of Pax7 expression in SCs was similar to that of the expression of the differentiation regulatory factor myogenin during the early stage of functional overload. However, the percentage of SCs that expressed Pax7 was markedly higher than that of the SCs that expressed myogenin. Coexpression of Pax7 and myogenin was not detected in SCs. In addition, the expression of cyclin-dependent kinase inhibitor p21, which regulates cell cycle arrest and differentiation, was not detected in Pax7-positive SCs. Conclusion:, These results suggest that Pax7-regulated self-renewal of SCs may be induced during the early stage of functional overload and may contribute to modulating the SC population in hypertrophied muscles. Furthermore, it was suggested that the numbers of SCs which underwent self-renewal may be higher than that of SCs which were provided as the additional myonuclei for hypertrophying myofibres. [source] Alterations of M-cadherin, neural cell adhesion molecule and , -catenin expression in satellite cells during overload-induced skeletal muscle hypertrophyACTA PHYSIOLOGICA, Issue 3 2006M. Ishido Abstract Aim:, Neural cell adhesion molecule (NCAM) and M-cadherin are cell adhesion molecules expressed on the surface of skeletal muscle satellite cell (SC). During myogenic morphogenesis, M-cadherin participates in mediating terminal differentiation and fusion of myoblasts by forming a complex with , -catenin and that NCAM contributes to myotube formation by fusion of myoblasts. Hypertrophy and hyperplasia of functionally overloaded skeletal muscle results from the fusion with SCs into the existing myofibres or new myofibre formation by SC,SC fusion. However, the alterations of NCAM, M-cadherin and , -catenin expressions in SCs in response to functional overload have not been investigated. Methods:, Using immunohistochemical approaches, we examined the temporal and spatial expression patterns of these factors expressed in SCs during the functional overload of skeletal muscles. Results:, Myofibres with SCs showing NCAM+/M-cadherin,, NCAM+/M-cadherin+ or NCAM,/M-cadherin+ were detected in overloaded muscles. The percentage changes of myofibres with SCs showing NCAM+/M-cadherin,, NCAM+/M-cadherin+ or NCAM,/M-cadherin+ were elevated in day-3 post-overloaded muscles, and then only the percentage changes of myofibres with SCs showing NCAM,/M-cadherin+ were significantly increased in day-7 post-overload muscles (P < 0.05). Both , -catenin and M-cadherin were co-localized throughout quiescent, proliferation and differentiation stages of SCs. Conclusion:, These results suggested that the expressions of NCAM, M-cadherin and , -catenin in SCs may be controlled by distinct regulatory mechanisms during functional overload, and that interactions among NCAM, M-cadherin and , -catenin in SCs may play important roles to contribute to overload-induced muscle hypertrophy via fusion with each other or into the existing myofibres of SCs. [source] Regulation of sperm flagellar motility activation and chemotaxis caused by egg-derived substance(s) in sea cucumberCYTOSKELETON, Issue 4 2009Masaya Morita Abstract The sea cucumber Holothuria atra is a broadcast spawner. Among broadcast spawners, fertilization occurs by means of an egg-derived substance(s) that induces sperm flagellar motility activation and chemotaxis. Holothuria atra sperm were quiescent in seawater, but exhibited flagellar motility activation near eggs with chorion (intact eggs). In addition, they moved in a helical motion toward intact eggs as well as a capillary filled with the water layer of the egg extracts, suggesting that an egg-derived compound(s) causes motility activation and chemotaxis. Furthermore, demembranated sperm flagella were reactivated in high pH (>7.8) solution without cAMP, and a phosphorylation assay using (,-32P)ATP showed that axonemal protein phosphorylation and dephosphorylation also occurred in a pH-dependent manner. These results suggest that the activation of sperm motility in holothurians is controlled by pH-sensitive changes in axonemal protein phosphorylation. Ca2+ concentration affected the swimming trajectory of demembranated sperm, indicating that Ca2+ -binding proteins present at the flagella may be associated with regulation of flagellar waveform. Moreover, the phosphorylation states of several axonemal proteins were Ca2+ -sensitive, indicating that Ca2+ impacts both kinase and phosphatase activities. In addition, in vivo sperm protein phosphorylation occurred after treatment with a water-soluble egg extract. Our results suggest that one or more egg-derived compounds activate motility and subsequent chemotactic behavior via Ca2+ -sensitive flagellar protein phosphorylation. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Muscle stem cells and model systems for their investigationDEVELOPMENTAL DYNAMICS, Issue 12 2007Nicolas Figeac Abstract Stem cells are characterized by their clonal ability both to generate differentiated progeny and to undergo self-renewal. Studies of adult mammalian organs have revealed stem cells in practically every tissue. In the adult skeletal muscle, satellite cells are the primary muscle stem cells, responsible for postnatal muscle growth, hypertrophy, and regeneration. In the past decade, several molecular markers have been found that identify satellite cells in quiescent and activated states. However, despite their prime importance, surprisingly little is known about the biology of satellite cells, as their analysis was for a long time hampered by a lack of genetically amenable experimental models where their properties can be dissected. Here, we review how the embryonic origin of satellite cells was discovered using chick and mouse model systems and discuss how cells from other sources can contribute to muscle regeneration. We present evidence for evolutionarily conserved properties of muscle stem cells and their identification in lower vertebrates and in the fruit fly. In Drosophila, muscle stem cells called adult muscle precursors (AMP) can be identified in embryos and in larvae by persistent expression of a myogenic basic helix,loop,helix factor Twist. AMP cells play a crucial role in the Drosophila life cycle, allowing de novo formation and regeneration of adult musculature during metamorphosis. Based on the premise that AMPs represent satellite-like cells of the fruit fly, important insight into the biology of vertebrate muscle stem cells can be gained from genetic analysis in Drosophila. Developmental Dynamics 236:3332,3342, 2007. © 2007 Wiley-Liss, Inc. [source] An SNF2 factor involved in mammalian development and cellular proliferationDEVELOPMENTAL DYNAMICS, Issue 1 2001Eric H. Raabe Abstract Members of the SNF2 (Sucrose Non-Fermenter) family of chromatin-remodeling proteins function in processes ranging from DNA repair to transcription to methylation. Using differential display, we recently identified a novel member of the SNF2 family that is highly expressed at the mRNA level in proliferating cells and is down-regulated during apoptosis. We have named this gene PASG (Proliferation-Associated SNF2-like Gene). Northern blot analysis of adult mouse tissues shows PASG to be highly expressed in proliferating organs such as thymus, bone marrow, and testis and absent from nonproliferative tissues such as brain and heart. In situ hybridization analysis of mouse embryos shows that PASG is differentially expressed during development, with highest expression in developing face, limbs, skeletal muscle, heart, and tail. In vitro, PASG expression correlates with a shift from a quiescent to a proliferative state. Mice null for PASG (also known as LSH or Hells) are reported to die perinatally, although the mechanism for lethality is unclear (Geiman and Muegge, 2000). To test the hypothesis that PASG functions in cell proliferation, we compared 5-bromodeoxyuridine (BrdU) incorporation in C33A cells transiently transfected with PASG versus empty vector and found that PASG transfected cells showed a significant decrease in the amount of BrdU incorporation. These findings suggest that PASG plays a role in cell proliferation and may function in the development of multiple cell lineages during murine embryogenesis. © 2001 Wiley-Liss, Inc. [source] Developmental and Quiescent Subsidiaries in the Asia Pacific: Evidence from Hong Kong, Singapore, Shanghai, and SydneyECONOMIC GEOGRAPHY, Issue 2 2003Jessie P. H. Poon Abstract: Examining "embedded" economic and social relations has become a popular theme among economic geographers who are interested in explaining the durability of place in supporting economic activities. This article explores the relationship between embeddedness and technology-oriented functions among three types of subsidiaries (regional headquarters, regional offices, and local offices) and for four cities: Hong Kong, Shanghai, Singapore, and Sydney. Using survey data from firms, we show that quiescent or branch plant-like subsidiaries, rather than developmental firms, dominate the region. But among developmental subsidiaries, returns on embeddedness are not always obvious. Embeddedness and developmental subsidiaries are most significantly correlated with manufacturing regional headquarters. However, a small group of subsidiaries (local and regional offices) also perform developmental functions, despite their relative newness and lack of embed-dedness in the region. [source] Droplet fusion by alternating current (AC) field electrocoalescence in microchannelsELECTROPHORESIS, Issue 19 2005Max Chabert Abstract We present a system for the electrocoalescence of microfluidic droplets immersed in an immiscible solvent, where the undeformed droplet diameters are comparable to the channel diameter. The electrodes are not in direct contact with the carrier liquid or the droplets, thereby minimizing the risk of cross-contamination between different coalescence events. Results are presented for the coalescence of buffered aqueous droplets in both quiescent and flowing fluorocarbon streams, and on-flight coalescence is demonstrated. The capillary-based system presented here is readily amenable to further miniaturization to any lab-on-a-chip application where the conductivity of the droplets is much greater than the conductivity of the stream containing them, and should aid in the further application of droplet microreactors to biological analyses. [source] Intralesional bovine papillomavirus DNA loads reflect severity of equine sarcoid diseaseEQUINE VETERINARY JOURNAL, Issue 4 2010R. HARALAMBUS Summary Reasons for performing study: Sarcoids are nonmetastasising, yet locally aggressive skin tumours that constitute the most frequent neoplasm in equids. Infection by bovine papillomaviruses types 1 and 2 (BPV-1, BPV-2) has been recognised as major causative factor in sarcoid pathogenesis, but a possible correlation of intralesional virus load with disease severity has not been established thus far. Hypothesis: Given the pathogenic role of BPV-1 and BPV-2 in sarcoid disease, we suggest that intralesional viral DNA concentration may reflect the degree of affection. Methods: Severity of disease was addressed by recording the tumour growth kinetics, lesion number and tumour type for 37 sarcoid-bearing horses and one donkey. Viral load was estimated via quantitative real-time PCR (qPCR) of the E2, E5, L1 and L2 genes from the BPV-1/-2 genome for one randomly selected lesion per horse and correlated with disease severity. Results: Quantitative PCR against E2 identified viral DNA concentrations ranging from 0,556 copies/tumour cell. Of 16 horses affected by quiescent, slowly growing single tumours or multiple mild-type lesions, 15 showed a viral load up to 1.4 copies per cell. In stark contrast, all equids (22/22) bearing rapidly growing and/or multiple aggressive sarcoids had a viral load between 3 and 569 copies per cell. Consistent results were obtained with qPCR against E5, L1 and L2. Conclusions: While tumours of the same clinical type carried variable virus load, confirming that viral titre does not determine clinical appearance, we identified a highly significant correlation between intralesional viral load and disease severity. Potential relevance: The rapid determination of BPV viral load will give a reliable marker for disease severity and may also be considered when establishing a therapeutic strategy. [source] When do the Costs of Spermatogenesis Constrain Sperm Expenditure?ETHOLOGY, Issue 1 2009Remarks on the Pattern of the Spermatogenic Cycle The costs of spermatogenesis constrain sperm expenditure when sperm production per day is limited. Thus, males are challenged to allocate available resources to sperm production and other life history functions. However, this prevailing assumption is not applicable to species in which spermatogenesis becomes quiescent during the breeding season. Males of these species prepare large quantities of sperm before the breeding season. Among these species, constraints on ejaculates have been intensively investigated in salamanders that deposit spermatophores. Although it is predicted that sperm expenditure should not be limited because of abundantly prepared sperm, spermatophore deposition is often limited during the breeding season when vas deferens are full of sperm. We tested a hypothesis regarding limited spermatophore deposition by measuring sperm quantity and volume of spermatophores sequentially deposited by male eastern newts Notophthalmus viridescens. A male newt rarely deposits more than three spermatophores per mating. If depletion of non-sperm components of spermatophores limits spermatophore deposition, we predicted that spermatophore volume decreases while sperm quantity remains constant as a male deposits more spermatophores. Alternatively, some regulative mechanisms allow a limited portion of available sperm to be expended per mating, in which sperm quantity is predicted to decrease while the spermatophore volume remains constant. Finally, depletion of non-sperm components may regulate sperm expenditure, which predicted that both spermatophore volume and sperm quantity decrease. We found that both sperm quantity and the spermatophore volume decreased as a male deposited more spermatophores during a single mating. Sperm expenditure was constrained without the costs involved in active spermatogenesis, and depletion of non-sperm components likely regulate sperm quantity loaded in spermatophores. In dissociated spermatogenesis, constrained sperm expenditure do not mean that costly spermatogenesis is directly limiting male mating capacity but rather suggest that the evolution of physiological mechanisms regulating sperm expenditure per mating maximizes male reproductive success. [source] Developmental expression of Na+ currents in mouse Purkinje neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2006Mark Fry Abstract As Purkinje neurons mature during postnatal development, they change from electrically quiescent to active and exhibit high frequency spontaneous action potentials. This change in electrical activity is determined by both alteration in ion channel expression and the acquisition of synaptic input. To gain a better understanding of the development the intrinsic electrical properties of these neurons, acutely isolated Purkinje neurons from mice aged postnatal day 4 (P4) to P18 were examined. This included recording action potential frequency, threshold, height and slope, and input resistance and capacitance. Changes in a number of these properties were observed, suggesting significant changes in voltage-gated Na+ currents. Because voltage-gated Na+ currents, including the transient, resurgent and persistent currents, are known to play important roles in generating spontaneous action potentials, the developmental changes in these currents were examined. A large increase in the density of transient current, resurgent current and persistent current was observed at times corresponding with changes in action potential properties. Interestingly, the developmental up-regulation of the persistent current and resurgent current occurred at rate which was faster than the up-regulation of the transient current. Moreover, the relative amplitudes of the persistent and resurgent currents increased in parallel, suggesting that they share a common basis. The data indicate that developmental up-regulation of Na+ currents plays a key role in the acquisition of Purkinje neuron excitability. [source] Regulation of Human Myometrial Contractility During Pregnancy and Labour: Are Calcium Homeostatic Pathways Important?EXPERIMENTAL PHYSIOLOGY, Issue 2 2001Rachel M. Tribe If we are to develop new strategies for the treatment and management of preterm and dysfunctional term labour, it is imperative that we improve current understanding of the control of human uterine activity. Despite many studies of animal pregnancy, there is a paucity of knowledge relating to the complex control of human myometrium during pregnancy. It is hypothesized that human myometrium is relatively quiescent during the majority of pregnancy and that as term approaches there is cascade of molecular events that prepare the uterus for labour. This review will consider the cellular mechanisms involved in the regulation of human myometrial activity and the modulation of these by hormonal and mechanical signals. In particular, the contribution of calcium homeostatic pathways to the control of human myometrial contractility during gestation will be discussed. [source] Hepatitis B virus X protein affects S phase progression leading to chromosome segregation defects by binding to damaged DNA binding protein 1,HEPATOLOGY, Issue 5 2008Silvia Martin-Lluesma Chronic hepatitis B virus (HBV) infection is a leading cause of hepatocellular carcinoma (HCC), but its role in the transformation process remains unclear. HBV encodes a small protein, known as HBx, which is required for infection and has been implicated in hepatocarcinogenesis. Here we show that HBx induces lagging chromosomes during mitosis, which in turn leads to formation of aberrant mitotic spindles and multinucleated cells. These effects require the binding of HBx to UV-damaged DNA binding protein 1 (DDB1), a protein involved in DNA repair and cell cycle regulation, and are unexpectedly attributable to HBx interfering with S-phase progression and not directly with mitotic events. HBx also affects S-phase and induces lagging chromosomes when expressed from its natural viral context and, consequently, exhibits deleterious activities in dividing, but not quiescent, hepatoma cells. Conclusion: In addition to its reported role in promoting HBV replication, the binding of HBx to DDB1 may induce genetic instability in regenerating hepatocytes and thereby contribute to HCC development, thus making this HBV,host protein interaction an attractive target for new therapeutic intervention. (HEPATOLOGY 2008.) [source] Maternal-infant transmission of hepatitis C virus infectionHEPATOLOGY, Issue 5B 2002Eve A. Roberts 555 University Ave. Mother-to-infant transmission of hepatitis C virus (HCV) is comparatively uncommon. The prevalence of antibody to HCV (anti-HCV) in pregnant women is 0.1% to 2.4%, although in some endemic areas it is much higher. The proportion of women with anti-HCV who have active infection with viremia is 60% to 70%. Transmission of HCV occurs only when serum HCV RNA is detectable and may be related to higher levels (above 106 copies per mL). The rate of mother-to-infant transmission is 4% to 7% per pregnancy in women with HCV viremia. Co-infection with human immunodeficiency virus (HIV) increases the rate of transmission 4 to 5 fold. The actual time and mode of transmission are not known. Elective Cesarean section is not recommended for women with chronic HCV infection alone. The role of treatment to prevent transmission is limited by the fetal toxicity of currently available medications for hepatitis C. Breast feeding poses no important risk of HCV transmission if nipples are not traumatized and maternal hepatitis C is quiescent. Pregnant women at high risk for HCV infection should be screened for anti-HCV, and HCV RNA testing should be performed if anti-HCV is positive. Infants of women with hepatitis C should be tested for HCV RNA on two occasions, between the ages of 2 and 6 months and again at 18 to 24 months, along with serum anti-HCV. The natural history of mother-to-infant hepatitis C remains uncertain, especially the course in the first year of life when some infants appear to have spontaneous resolution. [source] Maternal-infant transmission of hepatitis C virus infectionHEPATOLOGY, Issue S1 2002Eve A. Roberts M.D., FRCPC Mother-to-infant transmission of hepatitis C virus (HCV) is comparatively uncommon. The prevalence of antibody to HCV (anti-HCV) in pregnant women is 0.1% to 2.4%, although in some endemic areas it is much higher. The proportion of women with anti-HCV who have active infection with viremia is 60% to 70%. Transmission of HCV occurs only when serum HCV RNA is detectable and may be related to higher levels (above 106 copies per mL). The rate of mother-to-infant transmission is 4% to 7% per pregnancy in women with HCV viremia. Co-infection with human immunodeficiency virus (HIV) increases the rate of transmission 4 to 5 fold. The actual time and mode of transmission are not known. Elective Cesarean section is not recommended for women with chronic HCV infection alone. The role of treatment to prevent transmission is limited by the fetal toxicity of currently available medications for hepatitis C. Breast feeding poses no important risk of HCV transmission if nipples are not traumatized and maternal hepatitis C is quiescent. Pregnant women at high risk for HCV infection should be screened for anti-HCV, and HCV RNA testing should be performed if anti-HCV is positive. Infants of women with hepatitis C should be tested for HCV RNA on two occasions, between the ages of 2 and 6 months and again at 18 to 24 months, along with serum anti-HCV. The natural history of mother-to-infant hepatitis C remains uncertain, especially the course in the first year of life when some infants appear to have spontaneous resolution. (HEPATOLOGY 2002;36:S106,S113). [source] Proteome analysis of rat hepatic stellate cellsHEPATOLOGY, Issue 2 2000Dan Bach Kristensen Proteome analysis was performed on cellular and secreted proteins of normal (quiescent) and activated rat hepatic stellate cells. The stellate cells were activated either in vitro by cultivating quiescent stellate cells for 9 days or in vivo by injecting rats with carbon tetrachloride for 8 weeks. A total of 43 proteins/polypeptides were identified, which altered their expression levels when the cells were activated in vivo and/or in vitro. Twenty-seven of them showed similar changes in vivo and in vitro, including up-regulated proteins such as calcyclin, calgizzarin, and galectin-1 as well as down-regulated proteins such as liver carboxylesterase 10 and serine protease inhibitor 3. Sixteen of them showed different expression levels between in vivo and in vitro activated stellate cells. These results were reproducibly obtained in 3 independent experiments. The up-regulation of calcyclin, calgizzarin, and galectin-1, as well as the down-regulation of liver carboxylesterase 10 were directly confirmed in fibrotic liver tissues. Northern blots confirmed up-regulation of the messenger RNAs (mRNAs) of calcyclin, calgizzarin, and galectin-1 in activated stellate cells, indicating that these changes were controlled at the mRNA level. In addition a list compiling over 150 stellate cell proteins is presented. The data presented here thus provide a significant new protein-level insight into the activation of hepatic stellate cells, a key event in liver fibrogenesis. [source] Infancy is not a quiescent period of testicular developmentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2001Héctor E. Chemes Postnatal evolution of the testis in most laboratory animals is characterized by the close continuity between neonatal activation and pubertal development. In higher primates, infancy, a long period of variable duration, separates birth from the beginning of puberty. This period has been classically considered as a quiescent phase of testicular development, but is actually characterized by intense, yet inapparent activity. Testicular volume increases vigorously shortly after birth and in early infancy due to the growth in length of seminiferous cords. This longitudinal growth results from active proliferation of infantile Sertoli cells which otherwise display a unique array of functional capabilities (oestrogen and anti-müllerian hormone secretion, increase of FSH receptors and maximal response to FSH). Leydig cells also show recrudescence after birth, possibly determined by an active gonadotrophic-testicular axis which results in increased testosterone secretion of uncertain functional role. This postnatal activation slowly subsides during late infancy when periodic phases of activation of the hypothalamo-pituitary-testicular axis are paralleled by incomplete spermatogenic spurts. The beginning of puberty is marked by the simultaneous reawakening of Leydig cell function and succeeding phases of germ cell differentiation/degeneration which ultimately lead to final spermatogenic maturation. The marked testicular growth in this stage is due to progressive increase at seminiferous tubule diameter. Sertoli cells, which have reached mitotic arrest, develop and differentiate, establishing the seminiferous tubule barrier, fluid secretion and lumen formation, and acquiring cyclic morphological and metabolic variations characteristic of the mature stage. All of these modifications indicate that, far from being quiescent, the testis in primates experiences numerous changes during infancy, and that the potential for pubertal development and normal adult fertility depends on the successful completion of these changes. [source] Effect of IL-2-Bax, a novel interleukin-2-receptor-targeted chimeric protein, on bleomycin lung injury,INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2005Michael J. Segel Summary The role of lymphocytes in the pathogenesis of lung fibrosis is not clear, but the weight of the evidence supports a pro-fibrotic effect for lymphocytes. The high-affinity interleukin-2 receptor (haIL-2R) is expressed on activated, but not quiescent, T lymphocytes. This selective expression of haIL-2R provides the basis for therapeutic strategies that target IL-2R-expressing cells. We hypothesized that elimination of activated lymphocytes by IL-2R-targeted chimeric proteins might ameliorate lung fibrosis. We investigated the effects of IL-2-Bax, a novel apoptosis-inducing IL-2R-targeted chimeric protein, on bleomycin-induced lung injury in mice. Treatment groups included (i) a single intratracheal instillation of bleomycin and twice-daily intraperitoneal injections of IL-2-Bax; (ii) intratracheal bleomycin and intraperitoneal IL-2-PE664Glu, an older-generation chimeric protein; (iii) intratracheal bleomycin/intraperitoneal PBS; (iv) intratracheal saline/intraperitoneal PBS. Lung injury was evaluated 14 days after intratracheal instillation by cell count in bronchoalveolar lavage (BAL) fluid, semi-quantitative and quantitative histomorphological measurements and by biochemical analysis of lung hydroxyproline. Bleomycin induced a BAL lymphocytosis that was significantly attenuated by IL-2-Bax and IL-2-PE664Glu. However, morphometric parameters and lung hydroxyproline were unaffected by the chimeric proteins. These results show that IL-2-Bax reduces the lymphocytic infiltration of the lungs in response to bleomycin, but this effect is not accompanied by a decrease in lung fibrosis. [source] Immigrant Communities and Civil War*INTERNATIONAL MIGRATION REVIEW, Issue 1 2009David D. Laitin This paper explains why international migrants, who face numerous security and cultural threats in their host societies, are almost never implicated in civil war violence. This is quite different from situations of internal migration, which often set off violence that escalates to civil war proportions. The paper first lays out the stark contrast between the political implications of external and internal migration based on data adapted from the Minorities at Risk (MAR) dataset. It then explores the reasons for the low incidence of civil war violence for international migrants through an examination of three cases: Bahrain, which has a large expatriate community without political rights that has been politically quiescent; Estonia, where some 30 percent of the population are disaffected Russian-speakers linked to post-World War II migrations from other republics of the Soviet Union; and Pakistan, where the immigrant Muhajirs are a partial exception to the general pattern outlined in this paper. It concludes with a general statement of the relationship between immigration and rebellion, where the level of grievances is less consequential than the conditions that make insurgency pay off. [source] Recent modelling of sedimentation of suspended particles: a survey,IRRIGATION AND DRAINAGE, Issue 2 2001P. Boogerd modélisation de la sédimentation; dépostition granulaire; transport sédimentaire Abstract Recent literature on modelling of sedimentation was studied. Attention was paid to hydrodynamics, numerical simulation, settling velocity models, sediment and velocity distribution functions, and sediment transport equations. Many popular theories, e.g. those regarding stratification and preferential sweeping, are under discussion. The traditional view that large-scale, energy-containing fluid motions dominate the transport of particles is found to be under attack, as is the modification of the von Karman coefficient to account for the presence of sediment. It is unclear which model for hindered settling should be used under what circumstances, and the effect of particle distribution cannot yet be calculated. Even the most basic problems, such as settling of multiple and/or non-spherical particles in a quiescent liquid, still require research. In the field of sediment distribution functions new solutions are still not entirely satisfactory. Furthermore, the predictive value of transport rate models is still rather low, and several popular sediment transport functions consistently allow more degradation than aggradation. Copyright © 2001 John Wiley & Sons, Ltd. Ce document est une étude de la littérature récente de la modélisation de la sédimentation, en prêtant attention à la hydrodynamique, les simulations numériques, les modèles de la vitesse de déposer, les fonctions de la répartition du sédiment et de la vitesse, et les équations du transport sédimentaire. Beaucoup de théories modernes, celles concernant la stratification et l'entraînage préférentiel par exemple, sont en cours de discussion. L'idée traditionnelle que les mouvements fluides au champ extensif et contenant de l'energie dominent le transport granulaire est attaquée, ainsi que la modification du coefficient von Karman pour tenir compte de la présence du sédiment. Quel modèle à user pour la déposition gênée, et en quelle situation, n'est pas évident, et l'effet de la répartition granulométrique est incalculable. Même les problèmes les plus fondamentaux, comme la déposition d'e multiples granules ou des granules non-sphériques dans un liquide quiescent, ont besoin de recherche. Dans le domaine des fonctions de la répartition du sédiment, les nouvelles solutions ne sont pas encore entièrement satisfaisantes. En outre la valeur prédictionnaire des modèles de la vitesse de transport est encore assez basse, et plusieurs fonctions de transport populaires permettent constamment plus de dégradation que d'accroissement. Copyright © 2001 John Wiley & Sons, Ltd. [source] Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeianaJOURNAL OF ANATOMY, Issue 6 2005E. Sasso-Cerri Abstract In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis. [source] Role of O -linked ,- N -acetylglucosamine modification in the subcellular distribution of alpha4 phosphoprotein and Sp1 in rat lymphoma cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2005Shauna M. Dauphinee Abstract The mTOR alpha4 phosphoprotein is a prolactin (PRL)-downregulated gene product that is found in the nucleus of PRL-dependent rat Nb2 lymphoma cells. Alpha4 lacks a nuclear localization signal (NLS) and the mechanism of its nuclear targeting is unknown. Post-translational modification by O -linked ,- N -acetylglucosamine (O -GlcNAc) moieties has been implicated in the nuclear transport of some proteins, including transcription factor Sp1. The nucleocytoplasmic enzymes O -,- N -acetylglucosaminyltransferase (OGT) and O -,- N -acetylglucosaminidase (O -GlcNAcase) adds or remove O -GlcNAc moieties, respectively. If O -GlcNac moieties contribute to the nuclear targeting of alpha4, a decrease in O -GlcNAcylation (e.g., by inhibition of OGT) may redistribute alpha4 to the cytosol. The present study showed that alpha4 and Sp1 were both O -GlcNAcylated in quiescent and PRL-treated Nb2 cells. PRL alone or PRL,+,streptozotocin (STZ; an O -GlcNAcase inhibitor) significantly (P,,,0.05) increased the O -GlcNAc/alpha4 ratio above that in control quiescent cells. However, PRL,+,alloxan (ALX; an OGT inhibitor) or ALX alone did not decrease O -GlcNAcylation of alpha4 below that of controls and alpha4 remained nuclear. In comparison, PRL (±ALX/STZ) greatly increased Sp1 protein levels, caused a significant decrease in the GlcNAc/Sp1 ratio (P,,,0.05, n,=,3) as compared to controls and partially redistributed Sp1 to the cytosol. Finally, a 50% downregulation of OGT gene expression by small interfering RNA (i.e., siOGT) partially redistributed both alpha4 and Sp1 to the cytosol. The alpha4 protein partner PP2Ac had no detectable O -GlcNAc moieties and its nuclear distribution was not affected by siOGT. In summary, alpha4 and Sp1 contained O -GlcNAc moieties, which contributed to their nuclear targeting in Nb2 cells. © 2005 Wiley-Liss, Inc. [source] Inhibitory effect of osmotic concentration, potassium and pH on motility of the sperm of the North American burbot Lota lota maculosaJOURNAL OF FISH BIOLOGY, Issue 1 2007M. D. Zuccarelli Seminal plasma factors maintaining North American (NA) burbot Lota lota maculosa sperm quiescent were examined. Sperm were diluted into buffered saline solutions of various compositions and motility assessed. After 1 h in these solutions at 10° C, aliquots of the suspension were diluted with tap water and motility again assessed. Dilution of sperm in an incubation solution containing Ca2+ in the absence of K+ initiated sperm motility resulting in low motility when sperm were subsequently diluted in tap water. Incubation solutions with osmolalities >200 mOsm kg,1 and containing 12·5 mM K+ prevented the onset of sperm motility and were associated with maximal sperm motility upon dilution in tap water. Sperm maintained at lower osmolalities exhibited limited motility upon dilution in tap water indicating interdependence between K+ and osmolality in maintaining sperm quiescent in the presence of Ca2+. Sperm kept in incubation solution at pH values < c. 7·5 for 1 h demonstrated reduced motility when subsequently diluted in tap water. That motility of sperm was pH sensitive was further indicated by CO2 inhibition of motility. Therefore, NA burbot sperm are probably maintained in an immotile state, yet with potential for motility, by combination of high K+, osmolality and possibly pH. The results from this study differ from published information on sperm quiescence in the temporally and geographically distinct Eurasian burbot Lota lota lota. [source] Gonadal morphogenesis and sex differentiation in intraovarian embryos of the viviparous fish Zoarces viviparus (Teleostei, Perciformes, Zoarcidae): A histological and ultrastructural studyJOURNAL OF MORPHOLOGY, Issue 9 2006Tina H. Rasmussen Abstract It is essential to know the timing and process of normal gonadal differentiation and development in the specific species being investigated in order to evaluate the effect of exposure to endocrine-disrupting chemicals on these processes. In the present study gonadal sex differentiation and development were investigated in embryos of a viviparous species of marine fish, the eelpout, Zoarces viviparus, during their intraovarian development (early September to January) using light and electron microscopy. In both sexes of the embryos at the time of hatching (September 20) the initially undifferentiated paired bilobed gonad contains primordial germ cells. In the female embryos, ovarian differentiation, initiated 14 days posthatch (dph), is characterized by the initial formation of the endoovarian cavity of the single ovary as well as by the presence of some early meiotic oocytes in a chromatin-nucleolus stage. By 30 dph, the endoovarian cavity has formed. By 44 dph and onward, the ovary and the oocytes grow in size and at 134 dph, just prior to birth, the majority of the oocytes are at the perinucleolar stage of primary growth and definitive follicles have formed. In the presumptive bilobed testis of the male embryos, the germ cells (spermatogonia), in contrast to the germ cells of the ovary, remain quiescent and do not enter meiosis during intraovarian development. However, other structural (somatic) changes, such as the initial formation of the sperm duct (30 dph), the presence of blood vessels in the stromal areas of the testis (30 dph), and the appearance of developing testicular lobules (102 dph), indicate testicular differentiation. Ultrastructually, the features of the primordial germ cells, oogonia, and spermatogonia are similar, including nuage, mitochondria, endoplasmic reticulum, and Golgi complexes. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Kisspeptin and the Preovulatory Gonadotrophin-Releasing Hormone/Luteinising Hormone Surge in the Ewe: Basic Aspects and Potential Applications in the Control of OvulationJOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2010A. Caraty The identification of the neural mechanisms controlling ovulation in mammals has long been a ,holy grail' over recent decades, although the recent discovery of the kisspeptin systems has totally changed our views on this subject. Kisspeptin cells are the major link between gonadal steroids and gonadotrophin-releasing hormone (GnRH) neurones. In the female rodent, kisspeptin cells of the preoptic area are involved in the positive-feedback action of oestrogen on GnRH secretion, although the picture appears more complicated in the ewe. As in rodents, activation of preoptic kisspeptin neurones accompanies the GnRH surge in the ewe but an active role for arcuate kisspeptin neurones has also been proposed. Experimentally, kisspeptin is able to restore reproductive function when the hypothalamic-hypophyseal ovarian axis is quiescent. For example, i.v. infusion of a low dose of peptide in anoestrous ewes induces an immediate and sustained release of gonadotrophin, which subsides and then provokes a luteinising hormone (LH) surge a few hours later. This pharmacological intervention induces the same hormonal changes normally observed during the follicular phase of the oestrous cycle, including the secretion of oestrogen and its negative- and positive-feedback actions on the secretion of LH and follicle-stimulating hormone. Accordingly, a high percentage of kisspeptin-infused animals ovulated. Although the multiple facets of how the kisspeptin systems modulate GnRH secretion are not totally understood, the demonstration that exogenous kisspeptin administration can induce ovulation in anovulatory animals paves the way for future therapeutic applications aiming to control reproduction. [source] Withdrawal of corticosteroids in inflammatory bowel disease patients after dependency periods ranging from 2 to 45 years: a proposed methodALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 10 2009S. J. MURPHY Summary Background, Even in the biologic era, corticosteroid dependency in IBD patients is common and causes a lot of morbidity, but methods of withdrawal are not well described. Aim, To assess the effectiveness of a corticosteroid withdrawal method. Methods, Twelve patients (10 men, 2 women; 6 ulcerative colitis, 6 Crohn's disease), median age 53.5 years (range 29,75) were included. IBD patients with quiescent disease refractory to conventional weaning were transitioned to oral dexamethasone, educated about symptoms of the corticosteroid withdrawal syndrome (CWS) and weaned under the supervision of an endocrinologist. When patients failed to wean despite a slow weaning pace and their IBD remaining quiescent, low dose synthetic ACTH stimulation testing was performed to assess for adrenal insufficiency. Multivariate analysis was performed to assess predictors of a slow wean. Results, Median durations for disease and corticosteroid dependency were 21 (range 3,45) and 14 (range 2,45) years respectively. Ten patients (83%) were successfully weaned after a median follow-up from final wean of 38 months (range 5,73). Disease flares occurred in two patients, CWS in five and ACTH testing was performed in 10. Multivariate analysis showed that longer duration of corticosteroid use appeared to be associated with a slower wean (P = 0.056). Conclusions, Corticosteroid withdrawal using this protocol had a high success rate and durable effect and was effective in patients with long-standing (up to 45 years) dependency. As symptoms of CWS mimic symptoms of IBD disease flares, gastroenterologists may have difficulty distinguishing them, which may be a contributory factor to the frequency of corticosteroid dependency in IBD patients. [source] Recrudescence of sexual activity in a colony of the Mashona mole-rat (Cryptomys darlingi): an apparent case of incest avoidanceJOURNAL OF ZOOLOGY, Issue 2 2001M. Herbst Abstract Colonies of the Mashona mole-rat Cryptomys darlingi are founded from a single reproductive pair of animals that are genetically unrelated by descent. All non-reproductive animals are the progeny of the reproductive pair. Non-reproductive colony members do not seem to be suppressed from reproduction at the level of the pituitary. In colonies in which the reproductive female is removed or dies, there is strict incest avoidance and the colony remains reproductively quiescent. Reinstatement of sexual activity in a queenless colony may be brought about in the laboratory by the introduction of unfamiliar and unrelated adult males. In the queenless colony under study, there was a marked change in the dominance hierarchy with an increase in Landau's index of linearity from 0.61 to 1.0 on the introduction of two unrelated males. The two new males became the most dominant within the colony. All previously non-reproductive females exhibited heightened urinary oestradiol 17, and progesterone concentrations on the introduction of the males. However, it was only the older and most dominant non-reproductive female that became the new reproductive female and produced a litter of three pups 70 days after the initial introduction. [source] Review article: a conceptual approach to understanding the molecular mechanisms of cancer development in Barrett's oesophagusALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2001R. F. Souza Oesophageal adenocarcinoma is one of the most deadly human malignancies. Gastro-oesophageal reflux disease (GERD) has been established as a strong risk factor for oesophageal adenocarcinoma, and more than 40% of adult Americans experience regular GERD symptoms. GERD can be complicated by oesophagitis, and by replacement of oesophageal squamous mucosa with metaplastic, intestinal-type epithelium (Barrett's oesophagus) that is predisposed to malignancy. Cancers in Barrett's oesophagus arise through a sequence of genetic alterations which endow unlimited proliferative capacity upon the cells by affecting components of the cell cycle clock apparatus,the pivotal molecular machinery in the cell nucleus that controls whether a cell will proliferate, differentiate, become quiescent or die. This report describes how the genetic abnormalities that have been recognized in Barrett's oesophagus might promote carcinogenesis through effects on the cell cycle clock machinery. The goal of this review is to provide the clinician with a useful conceptual basis for evaluating studies on the molecular mechanisms underlying the progression from metaplasia to carcinoma in Barrett's oesophagus. [source] Rheological Investigations in Understanding Shear-Enhanced Crystallization of Isotactic Poly(propylene)/Multi-Walled Carbon Nanotube CompositesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 11 2007Ke Wang Abstract A novel experimental technique to follow the crystallization processes of poly(propylene)/MWCNT composites that experience a steady shear deformation using dynamic melt rheometry is described. The effects of heterogeneous nucleation, temperature, and preshear on the crystallization behaviors were determined. A quantitative evaluation of crystallization kinetics difference between quiescent and preshear conditions could be achieved. By combining rheology with POM, we demonstrate that two different crystallization processes account for the shear-enhanced crystallization at low and high temperatures, respectively. [source] Neoplastic hepatocyte growth associated with cyclin D1 redistribution from the cytoplasm to the nucleus in mouse hepatocarcinogenesisMOLECULAR CARCINOGENESIS, Issue 12 2006Masahiro Yamamoto Abstract Cyclin D1 overexpression is a frequent change in hepatocellular carcinomas (HCCs). Our present study demonstrated that cyclin D1 overexpression with abundant cyclin E, cdk4, cdk2, and p27Kip1 (p27) occurred in neoplastic hepatocytes from the early stage of mouse hepatocarcinogenesis. While cyclin D1 expression was mainly found in the cytoplasm of the tumor cells, it shifted to the nucleus in association with cell proliferation after the animals were subjected to a partial hepatectomy (PH), and then returned once more to the cytoplasm when the cells became quiescent. Inhibition of PI3 kinase (PI3K) by Ly294002 in mouse HCC cells in vitro suppressed the nuclear shift of cyclin D1 as well as cell proliferation, while PI3K activation by PTEN suppression failed to induce nuclear shift of cyclin D1, suggesting that PI3K activation is essential but not sufficient for the cyclin D1 nuclear shift. While MEK-ERK1/2 inhibition by PD98059 and mTOR inhibition by rapamycin affected the cyclin D1 nuclear shift and cell proliferation to a lesser extent, both these inhibitors reduced cyclin D1 levels. Finally, although p27, cdk4 and calmodulin (CaM) were detected in the cyclin D1 immunoprecipitates from both quiescent and proliferating HCC cells, Hsc70 and SSeCKS were detected only in the immunoprecipitate from quiescent cells, and p21Waf1/Cip1 (p21) was detected only in that from proliferating cells, suggesting that the cyclin D1 complex is different in quiescent and proliferating cells. These observations indicate that the nuclear/cytoplasmic localization of cyclin D1 plays an important role in the proliferation/quiescence of neoplastic hepatocytes. © 2006 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||